1. Technical Field
The field of art to which this invention pertains may be generally located in the class of devices relating to valves. Class 137, Fluid Handling, United States Patent Office Classification, appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Background Information
Present day industrial plants employ a variety of machines which are provided with fluid pressure control systems that are operated by air pressure. The fluid pressure control systems for such machines vary from machine to machine. Some prior art fluid pressure control systems employ a directional control valve provided with exhaust flow control valves which are integrally mounted in the directional control valve body, or in a cover plate for said valve. Other prior art fluid pressure control systems which require exhaust flow control valves employ a sandwich or interface plate that is mounted on a directional control valve manifold or base, and the exhaust flow control valves are mounted in the sandwich or interface plate. A problem created by the additional use of sandwich or interface plates, for adding exhaust flow control valves to a directional control valve structure, or by adding additional integral exhaust flow control valves, is that such additions enlarge the overall directional control valve structure, increase the cost and weight of the valve structure, and make such a valve structure more complex. The enlargement of a directional control valve structure by the use of integral flow control valves, or by the use of sandwich or interface plates, is a disadvantage, because in many instances the directional control valve structure must be mounted in a very small space or area on a machine that it is controlling, as for example a robotic device. A further disadvantage of the use of sandwich or interface plates for adding exhaust flow control valves to a directional control valve structure is that such plates add additional weight to the overall valve structure, which is a disadvantage when the valve must be employed on a robot arm which is moved between many operative positions.
It is a primary object of the present invention, to provide a novel valve base which overcomes the problems of increased cost, increased weight and enlarged valve structures, when it is required to provide a flow control function with the use of a sandwich or interface plate in a pneumatic control system.
It is another objection of the present invention to provide a novel valve base which is light in weight, compact in structure, and which is adapted to selectively provide an exhaust flow control function.
It is a further object of the present invention to provide a novel valve base for a directional control valve structure which does not require a sandwich or interface plate in order to provide an exhaust flow control function.
It is still another object of the present invention, to provide a novel valve base for a directional control valve structure which provides a low profile valve structure, yet which can be employed to provide an exhaust flow control function.